Automatic positioning mechanism for machine tools



Aug.20,1935. 5, A EN 2,012,249

AUTOMATIC POSITIONINQ MECHANISM FOR MACHINE TOOLS Filed Aug. 17, 1953 7 Sheets-Sheet 1.

Fij 1 BER/YARD 5/1555 Aug. 20,1935. B. sAssEN AUTOMATIC POSITIONING MECHANISM FOR MACHINE TOOLS Filed Aug 17, 1955 7 Sheets-Sheet 2 BEE/YARD 5/9555 Aug. 20, 1935. B. SASSEN 2,012,249

AUTOMATIC POSITIONING MECHANISM FOR MACHINE TOOLS Filed Aug. 17, 1953 7 Sheets-Sheet 3 BEKNAKD 5A SSEN Aug. 20, 1935. s ss 2,012,249

AUTOMATIC PQSITIONING MECHANISM FOR MACHINE TOOLS Filed Aug. 17, 1955' 7 Sheets-Sheet 4 Z] rw cm DO' BER/MR1) 5Asscw Aug. 20, 1935.

B. SASSEN AUTOMATIC POSITIONING MECHANISM FOR MACHINE TOOLS Filed Aug. 17, 1933 7 Sheets-Sheet 5 a [80 3x, I Fig j] BERNARD mass/v Aug. 20, 1935. B. SASSEN 9 2 AUTOMATIC vosmomue MECHANISM FOR MACHINE TOOLS Filed Aug. 17, 19:55 7 Sheets-Shet 6- BERNARD 56 556A! so: {mm/Mn;

Patented Aug. 20, 1935 AUTOMATIC POSITIONING MECHANISM FOR- MACHINE TOOLS Bernard Sassen, Cincinnati, Ohio, assignor to The Cincinnati Milling Machine Company, Cincinnati, Qhlo, a corporation of Ohio Application August 17, 1933, Serial No. 685,614

19 Claims.

This invention relates to machine tools and more particularly to improvements in automatic measuring or sizing devices therefor.

In the operation of machine tools, the size of the work is usually predeterminedduring set-up of the machine by relative adjustment between tool and work support and in such a manner that subsequent movement therebetween will yield the desired dimensions. In preparing to machine plane surfaces for instance, consideration may have to be given to the relative position of the tool and work along any one or all of the three rectangular coordinates while in round or circular work, attention is more particularly directed to the radial dimension. In any case, these adjustments have usually been effected manually, which is a slow and tedious process, especially in precision work or where several settings have to be made in the machining of a single piece.

One of the objects of this invention is to provide an improved mechanism for efiecting measurement along any axis of adjustment quickly and accurately thereby decreasing the set-up time and conversely increasing the productivity of the machine.

Another object of this invention is to provide an improved mechanism for the aforesaid purposes which may be preset for any prescribed measurement'and subsequently power actuated, to effect said measurement automatically and without further attention on the part of the operator.

A further object of this invention is to provide a mechanism of the character described which will operate at a fast rate during a major portion of the adjustment and then automatically decelerate thereby preventing overrun and insuring a quick and accurate setting.

An additionalobject of this invention is to provide an improved electrical control mechanism fo'rithe aforesaid purposes.

Other objects and advantages of the present invention should be-readily apparent by reference to the following specification considered in conjunction with the accompanying drawings illustrative of one embodiment thereof, but it will be understood that any modifications may be made in the specific structural details thereof within the scope of the appended claims, without departing from or exceeding the spirit of the invention.

Referring to the drawings in which like reference characters indicate like or similar parts:

Figure 1 isan elevation of a machine tool showing one form of the invention applied thereto.

Figure 2 is a diagram of the electrical control circuit embodying the principles of this invention.

Figure 3 is a vertical section through the meter box.

Figure i is a detail section on the line t--% of Figure 3.

Figure 5 is a detail section on the line 5-5 of Figure 3.

Figure 6 is a section on the line 6-6 of Figure 7.

Figure 7 is a section on the line 1-1 of Figure 1.

Figure 8 is a view showing the invention applied to another form of machine tool.

Figure 9 is a partial side elevation of the machine'shown in Figure 8.

Figure 10 is asection on the line ID-40 of Figure 8.

Figure 11 is a view showing the interior of the control box;

Figure 12 is a, detail view of the control mechanism for the reverse clutch of the machine shown in Figure 8.

Figure 13 is a view of a modified form of the invention.

Figure 14 is a'sectional view on the line 86-555 of Figure 3.

Figures 15 to 18 inclusive are diagrammatic views of the electrical circuit showing the connections for various settings of the stationary dials.

Figure 19 is a section through the starting button as viewed on line it-lt of Figure 2.

Figure 20 is a detail section on the. line 26-20 of Figure l9.

Figure 21 is a section on the line 2l--2l of Figure 3.

Figure 22 is a section on the line 2222 of Figure 3.

Figure 23 is a diagram of the rectifying circuit.

This invention proposes incorporating in a machine tool a mechanism which may be operatively connected to the actuator that effects adjustment along any axis of measurement and which may be pre-set, so that upon subsequent power operation, the prescribed distance will be measured automatically, thereby determining the size of the work.

One embodiment of this invention is illustrated in connection with a machine tool, such as that shown in Figure 1, in which the reference numeral I0 indicates a column or support, having one set of guideways ll formed thereon for reciprocably supporting a work table II; and another set of guideways l3 for adjustably receiving a tool carrier l4. In the present construction the tool is mounted in a tool spindle l5 which is retatably mounted in the carrier for power actuation.

In this type of machine, the tool is usually a rotary cutter, such as I6, which is adapted to be supported, by an arbor l'l, above the work table l2. If now the work piece to be tooled is of such size that it may be mounted directly upon the table l2, the determination of its thickness would be established by relative adjustment between the cutter and work support. In the machine shown, this relative adjustment is obtained by rotation of an elevating screw l8 which is attached at one end with the carrier for movement therewith and which passes through a nut I 9 fixed with the bed Ill. The screw l8 has a splined connection with a clutch member 20 which serves as the actuator for the screw.

A power driven transmission may be provided for rotating the actuator,and, as shown in Figures 1 and 7, may include a prime mover 2| mounted in the bed of the machine having a bevel gear 22 secured to the armature shaft thereof. This gear meshes with a pair of bevel gears 23 and 24 mounted for free rotation on the vertical shaft 25. Each of these gears have clutch faces 26 adapted for engagement with complementary clutch faces 21 formed on opposite sides of the reverser clutch 28. The bevel gears 23 and 24 are driven in opposite directions and therefore the axial position of the clutch 28 will determine the direction of rotation of shaft 25. The clutch 28 is provided with a shifter fork 29 pivotally mounted on shaft 39 which extends through the forward part of the machine for receiving the manual operating handle 3|. This handle has a spring pressed detent 32 in the outer end thereof adapted to cooperate with three sockets 33 formed in the side of the bed for retaining the clutch in any one of three positions. It will thus be seen thatthe shaft may be driven in either one of two directions; or that the clutch may be moved to a neutral position to disconnect all power from the shaft.

The shaft extends upward and'has mounted thereon a first pair of spur gears 34 and 35 which mesh respectively with spur gears 36 and 31 coaxial of the elevating screw l8; and a second pair of spur gears 38 and 39 meshing respectively with spur gears 40 and 4| mounted for free rotation on the shaft 42. 1

Referring to Figure 2, the gear 36 is adapted to be connected to the clutch member 20 by the magnetic clutch 43, while the gear 31 is adapted to be connected to the clutch 20 by the magnetic clutch 44. The gears 40 and 4| are adapted to be connected by electrical magnets and 46,v

respectively, to the clutch member 41 which is integrally secured to the shaft 42. The magnets 43 and 45 are electrically connected in parallel for simultaneous operation, and the magnets 44 and 45 are likewise connected in parallel for simultaneous operation. Attention is invited to the fact that the ratio of gears 34, 36 to gears 38, 49, and of gears 35, 31 to gears 39, 4| is such that regardless of whether the screw is being driven by gear 34 or gear 35, the same predetermined number of revolutions will be imparted to shaft 42 for each revolution of the screw. This insures that regardless of the speed of rotation of the screw,

thecounting mechanism will accurately record,

the distance traveled. It will be noted that the gear 34 is smaller than the gear 35, so that when the former is connected to the screw the slide M will be moved at a slow rate, and when the gear 35 is connected to the screw the slide will move at a fast rate. A two-position control switch 48 is provided for determining which pair of magnetic clutches is to be energized and therefore may be termed the rate control switch.

For the purpose of automatically recording any distance that the slide may travel, a linear measuring meter box 49 is attached to the machine and is connected to the shaft 42 through the following mechanism. A bevel gear 50, secured to the end of shaft 42, meshes with a bevel gear 5| fixed to the end of shaft 52. As shown in Figure 4, this shaft has a splined end 53 which is adapted to engage the splined bore 54 of bevel gear 55 that is journaled in the rear wall 55 of the box 49. This forms a detachable connection and makes it possible to remove the box 49 at any time desired and also facilitates assembly with the machine.

Mounted in the box 49 are two sets of dials, one set being termed the rotary dials because they are permanently connected with the screw l8 for rotation therewith, and the other set may be termed the adjustable dials, because these dials are adapted for manual adjustment to preselect the desired measurement that the slide is to be moved. In the initial set-up of the machine the rotary dials are so connected to the mechanism that they will all read zero when the axis of the cutter spindle is in the plane of the table.

The rotaryv dials are driven by the following mechanism: Referring to Figure 3 the bevel gear 55 meshes with bevel gear 51 secured to the end of vertical shaft 58 which has secured to its lower end a spiral gear 59 meshing with an equal spiral gear 60 as more particularly shown in Figure 14. A second spiral gear 6| keyed to the shaft 58, meshes with a spiral gear 62 integral on the hub of gear 63. The ratio of the spiral gears 6|, 62 is one to one so that one revolution of the shaft 58 will effect one revolution of gear 63. This spur gear meshes with an equal size spur gear 64 integrally secured with the rotatable dial member 65. The ratio of the spiral gears 59 and 60 is one to one so that the shaft 56 supporting spiral gear 60 will be rotated one revolution for one revolution of the rotatable dial 65. The shaft 86 serves to rotate a second rotatable dial 51, but this dial is in a one to ten ratio with respect to dial 65 so that if the dial 65 is graduated to thousandths of an inch, the dial 81 will record hundredths of an inch.

The actuation of the dial 6'! is intermittent however, rather than continuous, and to this end -a cam member 68 is keyed to the shaft 65 having an annular rib 69 formed thereon which is divided at- I0 to form a track for any one of a plurality of pins ll secured to a disk 12 pinned to a shaft 13. These pins are ten in number and are spaced from each other a distance equal to the thickness of the rib 69. At the division point 19 the rib has a hooked portion 14 which is adapted after completion of nine-tenths of a revolution of shaft 68 to engage the next pin and during dial 61 has made one revolution, a third rotary .dial is provided which is connected by a one to ten reduction mechanism with the shaft I8. This connecting means is similar to the reduction mechanism connecting shaft 66 to I3 and includes a spiral gear 8| keyed to shaft I3 meshing with spiral gear 82 fixed to the end of shaft 88 which shaft carries a cam member 84 similar .to the cam member 68. This cam member cooperates with the pin plate fixed to the end of shaft 86 so that during the last tenth of a complete revolution of shaft 83 the shaft 88 will be moved through one-tenth of a revolution. The shaft 86 is connected. by spiral gearing 81 to spur gear 88 which in turn meshes with the spur gear .88 fixed to the rotary dial 80. If so desired, a

fourth rotary dial may be provided for recording each revolution made by the rotary dial 80 in which case it would be connected to the shaft 86 through spiral gearing 9|, cam 92, pin plate 93 and spur gearing 94. There is thus provided four rotary dials, each one in succession being connected to the next one in a one-to-ten ratio, or in otherwords, in accordance withthe decimal system, and if the first dial is utilized for recording thousandths of an inch, the next dial will record hundredths of an inch, the next dial tenths ofan inch, and the last dial will record inches.

Associated with the respective rotary dials, are adjustable dials 96, W, 98 and 89 mounted for free rotation on the shaft and each provided with an integral worm gear 99 meshing with a worm I80 which, as shown in Figure 14, is secured to the end of a vertical shaft II. This shaft extends through the top of the meter box and is provided with a knurled operating handle I82. A pivoted-cover plate I03 is secured to the top of the box in adjacent relation to the various dials for access thereto for any adjusting purposes and is also provided with two sets of windows I04 and I05. The set of windows I M are opposite the rotary dials 65, 61, B0 and Stand in such position as to show only one figure on the dial at a time. The other set of windows I I35 are located opposite dials 96, 97, 98 and $9 and it will be noted that these are mounted in a row which is spaced from the row of windows I06. The row of windows I05 is utilized when preselecting a desired measurement and therefore are spaced from the other windows to avoid confusion therewith by the operator. The worm tilt may be in one-to-ten ratio with the worm gear I39 so that one revolution of the knob I82 will effect one tenth of a revolution of the dial. To avoid guess work in setting the dial, a spring pressed detent IIlI' may be mounted in the box to engage a single notch in a disk I82 integral with shaft I0! after each revolution thereof.

The electrical circuit for automatically controlling the operation of the magnetic clutches and thereby the starting and stopping of the prime mover 2i will now be explained. One terminal I86, I61, I08, and I09 of solenoids 43, 44, 45 and '46 respectively are connected in parallel by conductor lid to one of a pair of electrical mains III. The other terminals H2 and N3 of solenoids 43 and 45 are connected in parallel by the conductor II4 to the switch point II5. The remaining terminals II6 and II! of magnets 44 and 46 are connected by the conductor II8 to the switch point II9. These switch points are arranged upon opposite sides of the rate selector switch 48 so that when it is in one position the conductor I20 will be connected to the switch point H5 and magnets 43 and #5 will be energized to cause relatively slow movement of the spindle carrier; and when the switch 48 is in the other position, magnets, and 46 will be energized to effect a relatively high rate of movement of the spindle carrier. A spring I 2I normally maintains switch lever 48 in its low speed position.

The motor 2I is connected by conductor I22 directly to the power main III. The other terminal of the motor is connected by line I28 to the switch point I24 but serially through con- .tacts 255 and 258 normally closed by switch point 251, the purpose of which will be explained-hereafter. It will be-noted from Figure 2 that this line passes in series through the brake operating solenoid I25. This solenoid operates on the pivoted brake lever I26 which, has a. brake shoe I21 connected to one end thereof for engaging a portion of the carrier It. A spring I22 normally maintains the brake shoe in contact with the carrier but when the lines I22 and I23 are connected to the power mains the solenoid I25 will be operated to withdraw the brake shoe automatically during operation of the prime mover. A second switch point I29, in series with the switch point I24, is connected by the conductor ISB to the other power main ISI. A motor starting and stopping switch I32 is pivotally mounted at I33 for electrically connecting the switch points I24 and I29 and carries a contact block I34 formed of electrical conducting material for this purpose. The switch points IM and I29 may be of a resilient nature, such as spring pressed plungers having a limited amount of axial movement so as to insure equalization of the contact pressures of the two points andinsure proper electrical contact.

.The switch lever I 32 carries a second contact block I35 secured to its opposite end which is adapted to close the switch points I36 and I3? to complete the circuit to line 6%. A spring I38 is provided for normally maintaining the switch I32 open.

Means have been provided whereby the switch ldmay be moved to a high speed position by the main switch under certain conditions and comprises a pivoted interference link I39 which in its normal position engages a lug Idd projecting from the end of the switch lever 38. It is sometimes desired, however, as more fully explained hereafter, that the switch d8 should not be moved to a high speed position simultaneously with the main switch, that the link I39 be disengaged to permit operation or movement of the rate switch it from its high speed position to its low speed position without disturbing the position of the main switch. In order that these various functions may be performed automatically, a solenoid MI is provided having a reciprocable plung er I42 having a reduced portion I43 adapted to pass through an elongated slot Me in the link I39 so that the link may be moved up and down without interference from the plurmer, but the plunger, has an enlarged head I 45 for engaging and withdrawing the link from the path of movement of the lug I4iI. It will thus be seen that when the link is held in a withdrawn position that operation of the main switch will not effect operation of the rate selector switch, and further that when both switches have been moved to a closed position that withdrawal of the link I39 will permit movement of the switch 48 independent of the starting switch.

The main switch is closed by a push button, Figure 19, which includes a plunger I46 adapted to contact the main switch lever I32. This plunger has an enlarged cylindrical portion I41 in which is pivotally mounted a pair oi latch pawls I48. The lower end of the plunger slides in bore I49 formed in the end of the adjustable sleeve member I50. This sleeve has a shoulder I5I, and a spring I 53 is interposed between this shoulder and the shoulder I52 formed on the plunger for normally exerting an upward pressure on the plunger to maintain the same in a withdrawn position and normally just out of contact with the switch lever I32.

The lower end of the sleeve I50 is threaded in the surrounding housing for adjusting the position of the inner end I54 thereof so as todetermine the timing of contact with the inclined faces I55 formed on the latch pawls I48. A spring I56 is interposed between these pawls to normally maintain them in an outwardly projected position so that they will engage the lower end I51 of the hollow push button I58. A spring I59 is interposed between a shoulder I60 and a peripheral flange I6I formed on the lower end of the push button for normally maintaining the same in an upward position. A threaded sleeve I62 serves to limit the upward position of the push button.

The plunger I46 carries the contact piece 251 which is insulated from the plunger. This piece is movable with the plunger relative to the oppositely positioned contacts 255 and 256 and also to a second pair of oppositely positioned contacts 258 and 259. It will be noted from Figure 19 that the last pair of contacts will be the last to be closed upon upward movement of the plunger I46.

The operation of this device is as follows: When the operator depresses the button I58 the lower face I51 of the push button engages the projecting latch pawls I48 and thereby causes downward movement of the plunger I46 which in turn moves the switch member I32. This movement continues until the contact pieces I34 and I35 are about to engage the respective switch points, at which time the bevel faces I55 on the latch pawls will engage the upper end of the sleeve I58 and cause inward movement of the pawls. This inward movement will continue for the additional axial movement it is necessary to impart to the push button to effect complete closing of the switch. At the time the switch points are completely closed, the latch pawls should have been moved inward suilicient to clear the lower face I51 of the push button so that the spring I53 will come into action to eifect withlrawal of the plunger I46 even although the push button I58 is depressed by the operator. This mechanism acts as a safety feature to effect instant withdrawal of the plunger I46 even although the operators hand is still on the button and leaves the switch I32 free to open should the necessity arise before the operator has seen fit to release the push button. Furthermore, it will be noted that the circuit to the motor is not completed until the plunger has been withdrawn. A lock nut I64 is threaded on the end of the sleeve for securing the same in any adjustable position that determines the tripping of the plunger I46.

A pair of electrically operated latches have been provided for maintaining the switch levers I32 and 48 in their respective positions and includes the latch I 65, pivoted at I66, having a spring I61 for normally maintaining the same in a latching position. A second latch I68, pivoted at I69, has a spring I10 for normally maintaining the same in a position to latch the switch lever 48. The latch I66 has tripping magnet Ill, and the latch I66, tripping magnet I12, which magnets are connected in parallel to the conductors I13 and I14. Since these solenoids are connected in parallel, any energization of the lines I13 and I14 will effect simultaneous operation of both magnets, but it will be recalled that it was desirable that the mechanism operate at a high speed for a certain period and then at a low speed, and this requires that the latch I66 be released before the latch I in order to permit movement of the switch lever 46 to its low speed position independent of the starting switch I32.

Mechanical means have been provided for effecting this sequential operation and comprises a reciprocable interference bolt I15 which is adapted to be engaged by a boss I16 formed on the switch lever 48 so that as the same is raised it will lift the bolt I15 and move the head I16 thereof in an interfering position behind the head I11 of the latch lever I65, and it will be held in this position by the latch I68. In the operation of this device the lines I13 and I14 are energized I11 of latch I65 to frictionally engage the head I16 of interference member I15. The frictional engagement will be sufficient to prevent the interference member I15 from dropping by gravity and therefore the switch lever I32 will not be released at this time. Since the first energization of lines I13 and I14 is only momentary the magnet "I will be deenergized and this will permit the interference member I15 to drop by gravity so that upon the second energization of this pair of lines the latch will be free to be withdrawn and permit opening of the switch lever I32 by spring I38.

It will now be seen that if the magnets I1 I, I12 and I are all de-energized that actuation of the push button I58 will effect closing of both switch levers and automatic latching of the same in a closed position and also an automatic withdrawal of the plunger I46 from the path of movement of the switch lever I32. It will also be noted that when solenoid MI and magnet I12 are now energized that the switch lever 48 will be free to move from its high speed position to its low speed position. A subsequent energization of the magnet I1I will permit operation of the switch I32 by spring I38, thereby disconnecting the prime mover 2| from its source of power and also applying the brake I21 to insure instant stopp e of the slide.

The manner in which the control circuit is interconnected serially through the various dials for automatic control thereby in accordance with their respective relative positions, will now be considered and for the sake of clarity the connection will first be considered diagrammatically. In order to prevent arcing as much as possible at the contact points, a low potential transformer including a primary I18 which is connected by lines I19 and I 80 across the main power lines III and I3I; and a secondary I8I having terminals I82 and I83 has been provided. If direct current is desired the secondary I8I may be connected to a two-plate vacuum tube 266 as shown in Figure 23, the terminal I82 then being connected at an intermediate point in secondary coil while the terminal I83 would be connected to the middle point of the auxiliary secondary I8l' which furnishes the power for lighting the filament all in the usual manner of such devices. The terminal I82 is connected by line I13 through serial contacts 258 and 259 to the magnets HI and I12, and also by line I84 to the solenoid MI and the \push button interlock solenoid I85. The return line I14 from the solenoids HI and I12 is connected to the contact point I88 on the movable dial 65. This contact point cooperates with contact point I 81 on the fixed dial 96 which is permanently connected to contact point I89 on movable dial 61. The fixed dial 91 has an elongated contact plate I89 which extends circumferentially from the zero mark beyond the numeral I in one direction,

' and beyond the numeral 9 in the other direction. 20'

The purpose of this will be explained hereafter.

This contact plate is permanently connected at all times to the contact point I99 on the movable dial 88 which is adapted to cooperate with the contact point I9I on the fixed dial 98. The movable dial 90 has a contact point I92 which is permanently connected at all times to contact I9I and adapted to cooperate with contact I99 formed on the fixed dial 99. The contact I99 is connected byline I99 to the terminal I89 of the low potential transformer. The dial 81 also carries another pair of contact points I95 and I98 which are adapted to engage respectively the contacts I91 and I99 carried by the fixed dial 91. The contact point I99 is connected'by line I99 to one termime] of the solenoid III and contact I91 is connected by line 299 to the remaining terminal of solenoid I95. The contact I95 is connected by line 292 to line I19 while contact I98 is permanently connected by line 299 to contacts I81 and A brief description of some of the possible settings of the dials will now be given as it is believed that these will clarify the operation and control of the electrical circuit by the dials and reference may now be had to Figures l5, 16, 1'1

and 18.

In Figure it will be noted that all of the dials both stationary and movable, stand at zero reading which would be the position of the parts before any measuring is done. It will be noted that the circuit through magnets HI and I12 is closed, the current flowing from the terminal I83 of transformer I9I through line I99, contacts I93, I92, I9I, I99, I89, I89, I81, I89 and line I19, then through the magnets III, III in parallel and returning through line I19 to the other terminal I82 of the transformer. It will also be noted that the solenoid III is energized, the current flowing from the terminal I89 of the transformer through line I99, contacts I99, I92,

I9I, I90, I89, I88, line 299, back through contacts I98 and I99, the last contact being connected by conductor I99 to one terminal of solenoid III, the current continuing through line 2 I89 to the other terminal I82 oi the transformer. The push button interlock solenoid I85 is also energized, the current fiowing from the terminal I83 through line I99, contact I93, I92, I9I, I98, I89, I88, I81, I88 and line 292, contacts 5 I95, I91, line 299 to the solenoid I85 and returning through line I94'to the terminal I82 of the transformer. This means that the push button is held in a locked position by the interlock plunger 201 which is reciprocably mounted 'in the solenoid I85 and normally held in a non- I 89 to the terminal I82 of the transformer.

energization of their operating magnets HI and I12 respectively.

It will thus be apparent that the machine cannot be started while all of the dials are set at a zero reading due chiefiy' to the position of the push button interlock pin 201.

In Figure 16 the adjustable dial 98 has been positioned to give a reading of one thousandth of an inch. The adjustment of this one dial will disconnect contact I81 from contact I88 and thereby break the previously described circuit to magnets HI and I12 thereby releasing the latch members I11 and I88. These latches are now in a position to lock the switch members I32 and 98 when the same are moved. Since the contacts I98 and I98 are still in engagement, and this portion of the circuit is independent of contacts I88, I81 the solenoid III is still energized thereby holding the link I39 in its previously described position, but the opening of contacts I81 and I86 broke the circuit to solenoid I85 causing the spring 208 to come into action and effect withdrawal of the push button interlock plunger 201. It will now be apparent that the push button I58 can be depressed which will only operate the switch lever I32 due to the withdrawn position of the link I39. The switch lever, however, will not be locked in position until the downward movement of the push button has been completed. movement, the pawl members I98 will be moved inward thereby releasing the plunger I95. Upon closure of the switch I92 the dial driving mechanism will eiTect rotation of the dial 85 until the contact I88 carried thereby engages contact I 91. This will immediately close the circuit again through magnets HI and I12, eiiecting with drawal of the latch member I11 and opening of the switch I32 by the spring I38. This will effect complete stoppage of the machine.

In Figure 1'7 the adjustable dial 91 has been moved from the position shown in Figure 15 to a position giving a reading of ten thousandths of an inch. It will be noted, in this case, that due to the length of the arcuate-shaped contact piece I89 the circuit through the magnets III and I12 is not broken and therefore both of the latch members I11 and I89 will be held in a withdrawn position. It will be further noted, however, that although the contacts I88 and I91 are in engagement that contacts I95 and I99 have been separated. This will break the circuit through line 299 and solenoid I88 thereby releasing the push button for operation but the circuit through solenoid III is still complete, because contact I98 has moved into engagement with contact I95 the'current flowing from con- Upon completion of the downward tact I88, through line 202 contacts I95, I98 and I99, and returning from the solenoid through line It will therefore be seen that when the push button is depressed that-the latch I11 is not in position to catch the switch lever I32 but as soon as the plunger moves downward. the switch element 251 will open the circuit at contacts 258 and 259 thereby releasing latch I11 so that it may engage thelever. When the plunger I48 is fired or returned it will be noted that it first closes the circuit through the motor which causes a slight movement of the dial which is sufllcient to break the circuit at contacts I81 and I86 even although the switch member 251 re-engages contacts 258 and 259. The dial 65 will continue to rotate at a slow speed because the switch member- 48 was not closed in this operation, and when the numeral 9 on the dial 65 is opposite the numeral 6 on dial 96, the dial 61 will start to index and both dials will move simultaneously until contact I 86 engages contact I81 and completes the circuit through magnet I1I which will thereby cause the switch I32 to open by means of the spring I38 and the machine will stop instantaneously.

In Figure 18 the movable dials have been set to give a reading of eleven thousandths of an inch in which case the circuit through magnets HI and I12 will be broken due to the separation of contacts I81 and I86. Also the circuit through solenoid I4I will be broken due to the separation of contacts I81 and I86, In addition the circuit through solenoid I85 will be broken due to the separation of contacts I91 and I95. It will now be seen that the link I 93 is in position for the first time to engage the switch lever 48 and upon depression of the push button, both switch levers I32 and 48 will be locked by their respective latches I11 and I68. This will also move the head I16 of the interference member I15 to a position behind the latch I11. The machine will now start at a fast rate which will continue for one thousandth of an inch at which time contact I86 will engage contact I81 and the circuit will be completed through magnets HI and I12 which will only cause withdrawal of the latch I68, in the manner previously explained, and at the same time the circuit through solenoid I4I will be completed by contact I86 engaging contact I81. Since both the solenoid HI and magnet I12 are now energized, the switch 48 is free to move to its slow speed position under the action of its spring I 2I. The machine will now continue at a slow speed until the dial 65 has made one complete revolution at which time it will be in the same position as now shown in Figure 18 and then the indexing movement of the dial 61 will commence and both dials will move together until contact I86 re-engages the contact I81. This will cause a second closing of the circuit through magnet HI and the interference piece I16 having by this time dropped out by gravity from the path of movement of the latch I11, the latch is free to be withdrawn and the switch I32 opened by its spring I38. This will cause immediate stoppage of the machine. It will also be noted at this time that the contact I96 has been moved again into engagement with the contact I98 due to the indexing movement imparted to the dial 61 so that if a subsequent movement often thousandths of an inch or less is desired, the solenoid I will be energized and the link I39 will be in a withdrawn position so that the machine will operate at a slow rate of In Figure 2 the adjustable dials have been set to give a reading of 7.315 inches. In this case the circuit through all of the solenoids I85, HI, I" and I12 is broken due to the separation of the pair of contact points I92 and I93 as well as several of the others. This means that the push button is able to be actuated and that both switches will be closed and the machine will start operation at a high rate of speed. This will continue until the various movable dials 96, 86 and 81 have been indexed to give a reading of 7.305. At this reading the contact I86 will be in engagement with contact I81, contact I88 will engage contact I 89, contact I96 will engage contact I9I and contact I92 will engage contact I93. This will cause the first energization of magnets HI and I12 and thereby a slowing down of the machine due to the operation of switch 48. The dial 65 will continue to rotate after effecting momentary contact between points I86 and I81. until the second contact is made at which time the dial 61 will have been indexed to give a reading of 7.315. This will cause a second energization of magnet HI and opening of the switch I32 thereby stopping the machine.

In Figure 3 the construction of the various dials is shown whereby these various connections may be made and which will now be described. The adjustable dials 96, 91, 98 and 99 each have a flanged metallic hub member 2 I6 formed of electrical conducting material and the bore of each member is lined with insulating material 2 whereby the hub 2I6 may be insulated from the shaft 95. Surrounding the hub member 2| 6 is the annular member 2I2 which is formed of insulating material and molded or otherwise integrally secured on the hub. The member 2I2 has a shoulder 2 I3 to which is secured the worm gear 99 which serves as means for adjusting the dial. The member 2I2 also has an annular rib 2I4, the periphery of which carries the numerals which may be printed directly thereon, but preferably printed on a separate strip which may be attached thereto. The rotatable dials are similarly formed with a metallic hub member of electrical conducting material having a bore lined with insulating material and an exterior annular member having a shoulder thereon to which the driving gear is attached. These dials are mounted on the shaft 95 in the manner shown in Figure 3 and for free rotation relative to the shaft. It will be noted that the insulating sleeve 2 is flanged at one end so as to abut the flange of the sleeve of its cooperating rotatable dial so as to form a spacer therebetween and also to insulate one fixed dial from its cooperating rotatable dial.

A spring 2I5 surrounding an insulating sleeve 2I6 carried by the shaft 95 serves to maintain an end pressure on all of these dials so that certain parts are in constant electrical contact with one another. For instance, the hub of adjustable dial 96 contacts the hub of the rotatable dial 61 while the hub of dial 91 contacts the hub of dial 86 and the hub of dial 98 contacts the hub of dial 96. The hub of dial 65 is elongated beyond its circumscribing annular member 2I2 for receiving the brush 2" which is secured to the underside of the box by screw 2I8 but insulated therefrom by the sleeve 2I9 which is formed of insulating material. The construction of this brush is more particularly shown in Figure and is of U-shape so as to provide a certain amount of spring to insure a constant electrical contact with the hub. The screw 2I8 is secured in the bottom of a binding post 226 to which the conductor I14 is secured by the binding screw 22I.

Each of the adjustable dialswith exception of dial 91 has secured to the'fianged face of the hub member a wedge shaped contact point 222 corresponding to contacts I81, I9I and I93 of the diagrams. Each one of the rotatable dials 6|, 61, 86 and 96 have a contact plunger 223 held projected by a spring 224. These plungers correspond to contacts I86, I88. I96 and I92 of the diagrams.

The projection of these plunger-s is limited to a certain extent so that they will be sure to engage the contact 222 but will not project out far enough to continuously engage the flange of the hub because otherwise no make and break contact would be possible.

The hub 2 of dial 99 is extended similarly to hub of dial with a brush 2|? secured to the end of a second binding post 22B to which is secured the conductor use. The zero numerals on all of the dials whether adjustable or movable, are so arranged as to be in horizontal alignment when each plunger 223 is in engagement with its respective contact 222. When this is so, all the dials will read zero and the circuit from line lid will then pass through one binding post 2% and brush 28? to the hub of dial 65 having the reciprocable plunger 223 in electrical contact therewith and engaging the contact 222 on the hub of dial 9%. As previously mentioned, the hub of this dial is in constant electrical contact with the hub of dial 8i so that the current will continue to the plunger 223 carried by dial ti which in turn will be in engagement with a contact plate use carried by dial 9? and so on through the series oi dials to the hub oi the last member which is connected by the brush 2 ii to the binding post 2% having the conductor 9% secured therein. The dials 6i and @l have in addition conductor rings 225 and 226, Figures 21 and 22, respectively secured to their peripheries, the ring 225 having a brush 227i contacting therewith and electrically connected by the conductor 2&2 to the binding post to which is secured the line lid. The ring is connected by a brush to the binding post are in which is secured the conductor sec leading to the push button interlock solenoid.

The contacts W5 and it? are carried by the re-- speotive dials and st for connecting the line to the line iid. A second'pair of contacts W5 and 5% are also carried by the respective dials, the contact E96 being electrically connected to the hub of dial and thereby in electrical connection with line 577A? and in parallel with contacts and 223 carried by the dials $5 and 55.

The other contact is electrically connected to a second annular copper ring 23% carried by the dial on which bears a brush 285 depending from a binding post The line 095 which extends fromv the interlock solenoid M5 is connec ed to this binding post. As shown in Figures 21 and 22 the contacts it? and E98 are at different radial distances from the center of their re spective dials, while the contacts 9% and iiid have a portion which is at the same radiaf. distance from the center as the contact its but the contact E95 has an elongated portion for engaging the contact 8 9i. From this it will be seen that the contact Ml can only engage contact E95 while contact E98 is adapted to engage contacts 895 and I95 successively, these contacts being spaced at distance the sub-tended angle of which is equal to the sub-tended angle between any pair of numerals carried by the periphery of the dial.

A modified form of the invention is shown in Figure 13 in which the dials are graduated or sub-divided into 100 divisions, rather than in ten divisions as in the preceding form of the invention. Each one of these divisions may represent one thousandths of an inch as previously but one rotation of the dial will correspond to a hundred thousandths of an inch movementof the translatable slide rather than ten thousandths of an inch. Since the movable dial, such as 65, makes one revolution for each one hundred thousandths of an inch movement in the translatable support, the gearing ratio between the dial and lead screw will be one-tenth of what it was in the preceding construction, which means that, other things being equal, the dial will actually rotate slower than in the previous construction.

The second pair of dials 61 and 91' may also be graduated into 100 sub-divisions in which case the ratchet mechanism indicated generally by the reference numeral 233 will have a hundred to one ratio rather than a ten to one ratio. If the second pair of dials elf and 9'! are only divided into ten sub-divisions, then the ratchet mechanism at 233 may be a ten to one ratio similar to the previous embodiment, shown in Figure 3. If four decimal places are desired, then a third pair of dials may be connected in series in a similar mannor as shown in Figure 3.

The electrical circuit will be the same but it will be noted that the slow movement will now occur during the last one-hundred-thousandths of an inch rather than the last ten-thousandths of an inch.. Also if desired one connection may be eliminated to simplify the construction in which case the slow movement would occur for the last two-hundredths of an inch of movement.

In Figures 8, 9, l0, and 11 the invention is shown applied to a knee and column type machine and since the work for which the present measuring device is suitable is more conveniently performed with a vertical spindle, a vertical milling machine is shown although it is to be understood that the invention is equally applicable to one of the horizontal type. As shown in these figures the column 2% has guideways 235 therein for receiving and guiding a knee ass for vertical adjustment, which may be made by means of an elevating screw 23? operated by the manual control lever 238. The knee has horizontal guideways 235 for receiving a saddle Ztd which in turn has horizontal guideways Edi for receiving a horiaontally reciprocable table 2&2. The saddle may be adjusted toward and from the column by a lead screw 2% rotatable by the hand lever 2%. The drive motor 28 for the table, together with gearing such as shown in Figure i, may be supported by the saddle with the exception that the final gears are mounted on the vertical shaft 2&5

which then has the bevel gear 2% mounted on one end in operative engagement with bevel gears 2d? These last bevel gears are mounted coaxially or" the table'lead screw Edd which is journaled at opposite ends of the table and passes through a fixed nut 2% carried by the saddle. A reverser clutch 256i is interposed between the bevel gears for alternate connection therewith to determine the direction of rotation thereof. This clutch maybe operated by the handle iii and suitable intervening mechanism such as 52 more particularly shown in Figure 2. The switch box 252 may be attached to the side of the saddle as shown, with the push button I58 projecting in a convenient position for access by the operator. The meter box fit may be attached to the other side of the saddle with its drive shaft 52 directly connected by bevel gearing 256 to the lead screw M8. This direct connection eliminates as far as possible any lost play between the movement of the lead screw and the recording dials. It will be noted that the meter box, switch box and drive motor are all mounted upon the same support and therefore, may be readily inter-connected by fixed cables thereby requiring only one flexible connection from a main power source to this movable element.

There has thus been provided by this invention 'an electrical measuring device which may be readily aligned to any movable support of a machine tool for automatically and accurately measuring any desired distance from a predetermined reference line.

What is claimed is: i

1. In a device for automatically moving a machine tool slide a predetermined distance, the combination with a power actuator for the slide of a first plurality of dials graduated in accordance with the decimal system of measurement, means to adjust said dials to give a reading equal to the length to be moved, a second plurality of dials also graduated in accordance with the decimal system of measurement including a first dial coupled to the slide for actuation thereby, index mechanisms successively connecting the remaining dials for actuation by the first dial whereby each successive dial will be intermittently moved a fraction of a revolution for each complete revolution of the preceding dial, and means operable by the second plurality of dials on movement to a position yielding the same reading as the first plurality of dials to stop the slide.

2. In a device of the class described the combination of a. movable slide, a power actuator therefor, a pair of measuring dials having graduations thereon, means to adjust the dials to col lectively yield a desired measurement, a second pair of similarly graduated dials one of which is connected to the slide for movement thereby, index mechanism connecting the remaining dial to the first dial for recording the complete revolutions made thereby, means operable by the first dial upon completion of all but the last revolution thereof to efiect a reduction in the rate of movement of the slide, and additional means operable upon completion of the last revolution to stop the slide.

3. In a device of the class described the combination with a movable slide, of a preselecting measuring mechanism positionable to yield a desired measurement to be moved by the slide, a power actuator, means to couple the slide to the actuator for relative high speed movement, mechanism coupled to the slide for micrometrically recording the distance as moved, means-operable by said mechanism at a predetermined distance from the end of said movement to reduce the rate of slide movement, said mechanism also being operable upon yielding a recorded distance equal to the setting of said preselecting mechanism for stopping the movement of the slide.

4.-In a machine tool the combination with a movable slide, a prime mover and an electrically operated clutch for coupling the prime mover to the slide, of a control switch, manually operable means for closing the switch to energize the clutch, a latch mechanism for holding the switch in a closed position, a first graduated dial means pre-positionable to determine the length of slide movement, a second dial means simultaneously moved with the slide, co-operating contacts carried by the respective dials adapted to be closed when the reading of the two dial means isenergizatlon of said clutch, a brake for the slide,

, electrically operated means coupled in series with the prime mover for releasing the brake, manually operable means ior simultaneously closing said switches, a metering mechanism including a prepositionable portion for pre-selecting the length of slide movement, and a second portion coupled for simultaneous movement with the slide, and

means operable upon juxtaposition of said portions for automatically releasing said switches and applying the brake to stop the slide.

6. In a machine tool having a slide, a prime mover, and electrically operated clutches for coupling the prime mover to the slide in various ratios, a starting switch for determining operation of the prime mover, a rate control switch in series with the starting switch, manually operable means for simultaneously closing the starting switch and moving the rate control switch to a high speed position, a metering mechanism for measuring the length of slide movement, means automatically operable by said mechanism at a predetermined distance from the end of said movement for throwing the rate control switch to a slow speed position, and additional means operable by the metering mechanism for opening the starting switch upon completion of said movement.

7. In a machine tool having a slide, a prime mover, and electrically operated clutches for coupling the prime mover to the slide in different ratios, a rate control switch for said clutches, means normally maintaining said switch in a slow speed position,- a starting switch for the prime mover, an interlock for coupling the rate control switch for simultaneous movement with the starting switch, and means for automatically disconnecting said interlock when the length that the slide is to be moved in less than a predetermined amount.

8. In a machine tool having a work supportand a cutter support having a rotatable cutter journaled therein, the combination with a rotatable screw for effecting adjustment of one of said supports laterally of the other, and a prime mover, of means for controlling said movement including a control box having a rotatable part adapted to be detachably, operatively connected to the screw, prepositionable means in the control box for predetermining the length of said movement, means operable by said member for concurrently measuring the movement as effected and control means operable when the reading of each of said means is the same to disconnect the prime mover from the screw.

- 9. In a machine tool having a pair of supports, one of which is movable transversely of the other for eflfecting a predetermined relative movement between a cutter and a work piece, the combination with an actuator for effecting said relative movement, and a prime mover therefore, of a control box, a control circuit including a power operable clutch for connecting the prime mover to the actuatonsaid circuit terminating at the control box, a first set of dials mounted in the box and prepositionable to predetermine the length of said movement, a set of horizontally arranged windows cooperating with said dials, a second set of dials journaled in the control box and operatively connected for movement with the actuator, a second set of windows aligned in a difierent plane from the first set of windows for concurrently recording the movement as eifected, and means operable by said second set of dials when rotated to give a reading equal to the reading of 7 2,012,249 the first set of dialsfor closing the termini of said control circuit .and cause de-energization of said clutch and thereby disconnection of the prime mover from said actuator.

10. In a machine tool the combination with a H movable slide, a prime mover, and an electrically operated clutch for coupling the prime mover to the slide of a control switch, manually operable means for closing the switch to energizesaid clutch, a latch mechanism for holding the switch including cooperating contacts carried by the re- I spective dial means adapted to be closed when the reading of the twotdials means is the same to efiect tripping of said latch mechanism,'and additional control means between the prime mover ated slide for determining the direction of said movement, of a control switch, manually operable means for closing the switch to energize the clutch, a latch mechanism for holding the switch in a closed position, a first graduated dial means prepositionable to determine the length of movement in either direction, a second dial means simultaneously movable with the actuated slide, cooperating contacts carried by the respective dials and adapted to be closed when the reading of the two dials means is the same, and a control circuit in series with said contacts for tripping said latch mechanism and thereby opening said control switch to stop the slide regardless of its direction of movement.

12. In a device for automatically translating a part a predetermined distance, the combination of a plurality of adjustable dials, a plurality of movable dials, means to position the adjustable dials to indicate the distance to be moved by the part in opposite directions, a source of power, means for connecting the part to said source for movement thereby, means operatively connecting the movable dials for simultaneous movement with the part, power means operable for disconnecting the source of power from said part and including a control circuithaving one terminusin the adjustable dials, said circuit having a second terminus in the movable dials, said termini adapted to be closed when the movable dials have traveled the same amount as the adjustable dials were prepositioned.

13. In a device for automatically translating a movable part of a machine tool a prescribed distance, the combination of a source of power, branch transmissions actuated thereby at difiercut rates, means for connecting the movable part with one of said transmissions for movement thereby, a plurality of graduated dials operatively connected for simultaneous movement with'the part, and means automatically operable by said dials upon indication thereby that the movableautomatically effecting .a prescribed relative translation between the supports including a prime mover, branch transmissions actuated thereby at different rates, a plurality of adjustable and movable graduated dials, means to position theadjustable dials to indicate the distance to be moved by the support, means for connecting one of said supports selectively with one of said transmissions determinable by the position of said adjustable dials, means operatively connecting the movable dials for simultaneous movement with the movable support, and means automatically operable when the reading of the movable dials is equal to the reading of the adjustable dials for disconnecting the movable support from said transmissions.

15. In a device for automatically measuring the power movement of a machine tool slide having a prime mover and branch transmissions actuated thereby at different rates for selective connection with the slide, the combination of a first plurality of graduated members prepositionable in accordance with the distance the slide is to be moved, a second plurality of graduated members operatively coupled for simultaneous movement with the slide, means governed by the position of the first plurality of dials for connecting the slide with one or the other of said transmissions and means operable by the second plurality of dials upon yielding a reading equal to the reading of the first plurality of diais for automatically disconnecting the slide from said transmissions.

16. A measuring device for a machine tool slide including a prime mover, a pair of branch transmissions operabie by the prime mover at difierent rates, power operable clutches for connecting either transmission to the slide for actuation thereby, a, first means prepositionable to indicate micrometrically the distance to be moved, said means selectively determining the clutch to be energized, a second means employed for movement with the slide to indicate the distance concurrently moved, manually operable means for closing a circuit through the selected clutch to cause movement of the slide, and means automatically operable for opening said circuit after the slide has moved the prescribed measured distance. 1

17. An automatic measuring means for machine tools having a movable slide, a prime mover and branch transmissions actuable by the prime mover for selective connection with the slide ineluding power operable clutches for selectively connecting the transmissions with the slide, a selector switch fordetennining energization of the clutches, a power control circuit leading ,to said switch, manually operable means for closing said circuit to the switch, and means automatically operable by the slide after a predetermined movement thereof for opening said circuit and deenergizing the connected clutch.

18. In a device for automatically moving a mato the slide for actuation therewith, motion trans-- mitting connections-successively connecting the remaining dials for intermittent actuation by the first dial and means operable by the second plurality of dials upon yielding a reading equal to said prescribed distance to stop the movement of the slide. I

- 19. In a device for automatically translating a movable slide of the machine tool a predetermined distance in either one of two directions with respect to a tool, the combination of means for determining the direction of movement, a plurality of adjustable and movable graduated dials,.means to position the adjustable dials to indicate the distance to be moved in the prescribed direction, a source of power, means for connecting the slide with said source for movement thereby, said movable dials being operatively connected for simultaneous movement with the part regardless of its direction of movement, and power means operable for disconnecting the slide from the source of power including a control circuit having termini in the adjustable and movable dials respectively and adapted to be closed when the reading of one set of dials equals the reading of the other set of dials. 

